How much to put into house

[Lue Brooks]

Hi I recently bought my first property a few months ago. Originally I budgeted 20k for my rehab cost. I did not do anything to get this figure I just had the money that I was saving for a down payment (which I did not need to make since I had used a VA loan). My question is how can I accurately determine how much I should put into my duplex? I have spent some money on certain things to get done but I have been reflecting on things and have figured there is probably a better way to determine how much I should actually spend. Can someone point me in the right direction or give me their advice?